Various document processing systems, such as in an inserting machine, require that a document is aligned relative to a particular station in the system prior to being processed at the station. Typically, this is accomplished by registering a particular edge of the document in a particular direction in the system. For example, documents must be aligned before being conveyed to a folding apparatus to achieve a proper fold. Also, enclosures which are to be inserted into an envelope should be aligned relative to the envelope prior to insertion in order to avoid processing difficulties. Furthermore, some documents which are to be transported away from a particular queuing station, to another adjacent document raceway, should be aligned at the queuing station relative to the raceway, in order to facilitate the processing of the documents.
Devices which register a particular edge of a document to a particular direction are known. See, for example, U.S. Pat. Nos. 3,637,203, 4,078,790 and 4,925,180, which utilize stops that pivot into position to stop the advancement of documents being conveyed in a particular direction. Some registration devices, such as stationary side guides, perform the task of aligning the document while the document is being conveyed. Other devices, such as a "queuing" station, perform the dual task of aligning the document and stopping the document until the next successive station is ready to receive the document for further processing. Typically, queuing stations comprise mechanisms which register the document by stopping, i.e., queuing, the document. Queuing stations are typically configured to handle documents of a particular length and are not easily reconfigured to handle sheets of a different length. Queuing stations are generally comprised of a complex mechanical design that is subject to frequent mechanical failure. For this reason, a reconfiguration of a queuing station normally requires a service call by a skilled technician.
In U.S. patent application Ser. No. 808,863, noted previously herein, a document registration apparatus in the form of a queuing station is disclosed. The apparatus has a plurality of registration stops for stopping the conveyance of a document and registering a particular edge of a document to a particular direction in the apparatus. The registration apparatus also includes at least one pinch roller for moving the registered document away from the apparatus for further processing. The document registration apparatus also includes a jam access hinge for providing access to a jammed document. In U.S. patent application Ser. No. 906,200, noted previously herein, a similar document registration apparatus is disclosed with additional structure for performing skew adjustment. In U.S. patent application Ser. No. 906,170, noted previously herein, a further document registration apparatus is disclosed with additional structure for handling various sized documents.
Generally, during the stacking and registration of documents there is always the potential for the documents to become shingled, i.e., the top document in the stack is not directly above the lower documents but slightly shifted forward or backward, as they are conveyed from a stacking and registration area. Thus, the design and operation of a queuing station may result in undesirable shingling of documents.
The aforementioned document registration apparatus of U.S. applications Ser. Nos. 808,863, 906,200, and 906,170 include pinch rollers cooperatively operating with transport belts to remove the documents from the queuing station. The pinch rollers pivot into engagement with the stack as the registration stops pivot out of the way. Although this arrangement has been found to reduce the shingling of the stack of documents, it has not eliminated such shingling.